108 PLEURO-PNEUMONIA AND INOCULATION. 
duce lung disease by inoculating another part of the animal, 
but we can produce a disease similar in its character, in 
another part of the animal, to that which we find produced 
naturally in the lungs/ 5 
It is curious to read the reasons adduced as proof that the 
disease is contagious. If inoculation of a herd of cattle had 
been attempted with the parts of the lungs obtained from 
animals in a very healthy state, would the same inflammatory 
condition of the parts not have been induced, with the other 
collateral symptoms which follow inoculation, with the 
matter from the lungs of an animal affected with pleuro¬ 
pneumonia ? If so, what becomes of the inference that pleuro¬ 
pneumonia can be propagated by inoculation? Mr. Pottie 
considers it both a preventive and curative ; but to be effective 
when the animal is in a bad state, inoculation must be per¬ 
formed severely and in vital parts. He had operated upon 
seventy-seven cattle, which he had seen several times and 
could speak positively of. The following extract gives the 
details of his method of executing the operation of inocu¬ 
lation : 
“ We inoculated the greater number in the tail; we made 
a slit in the tail, put in a small piece of diseased lung, and 
rolled a worsted thread about it. In the course of five days 
the majority of these showed febrile symptoms—saliva flowing 
from the mouth, dull, hanging head, and so on. In the 
course of four days the tail was perceptibly swollen; this 
swelling would sometimes continue in the majority of cases 
till the seventeenth day, and in those that went on favorably 
after that time the swelling would begin to abate. Those that 
did not get on favorably would be longer; some would be six 
weeks or two months before they got better. In the latter 
cases the tail was more sw r ollen, and the swelling extended up 
the tail. Others we inoculated in the forearm; we took a 
piece of tow and saturated it in the matter obtained from the 
diseased lung/ 5 In reply to the question, Cf In what part did 
you insert it ? 55 this witness stated, 6C In the muscle of the 
forearm, in the anterior part; I inserted the tow deep in the 
muscle. I had a conversation with Mr. M‘Laurin about 
this mode of inoculation, and he told me the result in the 
case of some cattle he had experimented upon ; and I reasoned 
in my own mind that the tail was not the most suitable place, 
for there was no muscle to form a suppurating cyst, so as to 
throw off any excess of virus, or any quantity of deleterious 
matter that might collect there—that part of the tail near the 
point being composed principally of skin, blood-vessels, 
nerves, and bones. The lung was put into a dish and squeezed 
